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１９９１～１９９４年热带中东太平洋海温持续４ａ多出现正距平。Ｎｉｎｏ３指数一直为正值。在此正距平背景下，产生了两次振荡和３次ＥｌＮｉｎｏ暖期。在此期间赤道东太平洋海温在±５°纬度范围内发生了两次负距平的变化，形成了一个狭窄的温度梯度很大的“冷核”，而赤道外的中纬度海洋则持续维持两个正海温距平。这一时期海表温度资料ＥＯＦ分析的结果进一步表明，第一特征向量的空间分布实际上反映了上述冷核特征。１９９１～１９９４年的ＥＮＳＯ事件主要是低频分量发生了较大异常，赤道低层纬向风和高层西风在前期减弱（１９９１－０１—１９９２－０５），后期加强（１９９２－０６—１９９４－０１１）。无论是海温还是风场的低频分量都表现出一次ＥＮＳＯ循环的特征。因此作者认为，虽然Ｎｉｎｏ３指数等在这４ａ多期间均为正值，但是大气和海洋耦合系统的低频变化部分只发生了一次完整的ＥＮＳＯ循环过程。１９９１年至１９９２年上半年对应于ＥｌＮｉｎｏ暖位相，１９９２年下半年至１９９４年底对应于ＬａＮｉｎａ冷位相。但是这个冷位相没有能够得到充分发展，只出现两次极狭窄的冷核。冷位相的明显“夭折”，而代之以出现两次较弱的增暖，可能与季节内尺度的大气强迫与低频变化部分的?
During the period from 1991 to 1994, the mean temperature of the tropical mid-eastern Pacific surged for more than 4 years with positive anomalies. Nino3 index has always been positive. In this positive anomalous setting, two oscillations and three ElNino warm periods were generated. During this period, the equatorial Eastern Pacific SST experienced two negative anomalies within ± 5 ° latitude, forming a narrow “cold core” with a large temperature gradient while the mid-latitude off-equatorial ocean continued to maintain Two positive sea temperature anomalies. The EOF analysis of the sea surface temperature data during this period further shows that the spatial distribution of the first eigenvector actually reflects the above cold core features. The ENSO events of 1991-1994 mainly caused large anomalies in the low frequency components. The lower equatorial zonal winds and the upper westerlies weakened in the early period (1991-01-1992-05) and the later strengthened (1992-06-1994-011). Both the SST and the low-frequency components of the wind field show the characteristics of an ENSO cycle. Therefore, the author believes that although the Nino3 index is positive during all four years, only a complete ENSO cycle occurs in the low frequency variation of the coupled atmosphere and ocean system. From 1991 to the first half of 1992, corresponding to the warm ElNino phase, the second half of 1992 to the end of 1994 corresponds to the LaNina cold phase. However, this cold phase has not been fully developed, with only two very narrow cold nuclei. Obviously, “abortive” phase of cold phase, and replaced by the emergence of two weaker warming, may be associated with the seasonal scale of atmospheric forcing and low-frequency changes in the part?